Semiconductor device having multiple substrates

ABSTRACT

A semiconductor device includes a physical quantity sensor with a movable electrode disposed in a third layer of a first substrate, a fixed electrode in the third layer and a loop layer. The movable electrode and the fixed electrode are insulated by a second layer of the first substrate, and a loop bump disposed between the first substrate and a second substrate and surrounding the movable portion. The loop layer in the third layer is coupled with the second substrate via the loop bump.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/268,524filed on Nov. 8, 2005, which is a divisional of application Ser. No.10/806,274 filed on Mar. 23, 2004, now U.S. Pat. No. 6,979,873, each ofwhich is based on Japanese Patent Application Nos. 2003-88934 filed onMar. 27, 2003, and No. 2003-430049 filed on Dec. 25, 2003, thedisclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a semiconductor device having multiplesubstrates.

BACKGROUND OF THE INVENTION

A semiconductor device 101 is disclosed, for example, in Japanese PatentApplication Publication No. 2001-227902 (i.e., U.S. Pat. No. 6,316,840).The device 101 includes a sensor module 111 for detecting physicalquantity such as acceleration, pressure and angular rate, as shown inFIG. 17. The sensor module 111 provides an acceleration sensor, apressure sensor or an angular rate sensor. In the sensor module 111, amovable portion 50 is disposed on a principal plane of a sensorsubstrate, i.e., a sensor chip 52. The sensor chip 52 includes at leastthe movable portion 50 and an electric device (not shown). The electricdevice outputs an electric signal corresponding to a displacement of themovable portion 50. The electric signal outputted from the electricdevice is transmitted to a processing substrate, i.e., a signalprocessor 53 through a bump 21. The signal processor 53 performs apredetermined signal processing so that the physical quantity isdetected.

The signal processor 53 is provided by an application specificintegrated circuit (i.e., ASIC) so that the signal processor 53calculates the physical quantity such as the acceleration, the pressureor the angular rate on the basis of the electric signal outputted fromthe sensor chip 52. Further, the signal processor 53 sends apredetermined control signal to the sensor chip 52 so that the movableportion 50 and the electric device are controlled electrically.

The sensor chip 52 and the signal processor 53 are mounted on a die pad55 of a lead frame. The signal processor 53 is electrically connected toan inner lead 56 through a wire 54. The sensor chip 52 and the signalprocessor 53 together with the die pad 55 and the inner lead 56 aresealed in a resin mold 57 so as to provide a resin mold package.

The die pad 55 of the sensor module 111 is disposed below the inner lead56. Specifically, the die pad 55 is disposed at lower position lowerthan the inner lead 56 so as to provide a low die pad construction. Thisconstruction provides that the height of the inner lead 56 is almost thesame as the height of semiconductor parts such as the signal processor53 disposed on the die pad 55. Therefore, the wire 54 is easily bondedbetween the inner lead 56 and the semiconductor parts.

It is required to secure a movement (i.e., displacement) of the movableportion 50. Specifically, it is required for the movable portion 50 tomove smoothly. In general, the movable portion 50 is covered with acasing so that the casing prevents resin composing the resin mold 57from penetrating into the casing. However, total number of parts isincreased because of the casing. Therefore, manufacturing cost isincreased. Further, it is necessitated to bond the casing to the sensorchip 52. Therefore, additional manufacturing process is necessitated sothat the manufacturing cost is much increased.

In view of the above problem, in the semiconductor device 101, thesignal processor 53 is disposed on the die pad 55, and the sensor chip52 is disposed on the signal processor 53. A resin sealing 70 sealsbetween the periphery of the sensor chip 52 and the principal plane ofthe signal processor 53. The resin sealing 70 is disposed all around theperiphery of the sensor chip 52 so that a closed spacing 71 is providedby the resin sealing 70, the sensor chip 52 and the signal processor 53.The sensor chip 52 includes multiple bumps 21 disposed on the principalplane. The bumps 21 are connected to electrodes disposed on theprincipal plane of the signal processor 53 so that the sensor chip 52electrically connects to the signal processor 53. The signal processor53 is connected to the inner lead 56 through the wire 54. Thus, theresin material composing the resin mold 57 is prevented from penetratinginto the closed spacing 71 so that the movable portion 50 can movesmoothly.

However, it is necessitated to protect the sensor module 111 fromoutside disturbance such as noise. Therefore, a shield (not shown) isnecessitated for protecting the sensor module 111. The shield made ofmetal and the like is disposed on the sensor module 111. Thus, totalnumber of parts of the semiconductor device 101 is increased because ofthe additional shield. Therefore, additional manufacturing process isnecessitated so that the manufacturing cost of the device 101 isincreased.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, it is an object of the presentinvention to provide a semiconductor device having multiple substrates.Specifically, the device is protected from outside disturbance withoutadding an additional shield.

A semiconductor device includes a first substrate including first,second and third layers; and a second substrate including fourth, fifthand sixth layers. The first substrate provides an electric device. Thesecond substrate provides a physical quantity sensor. The first layer ofthe first substrate and the fourth layer of the second substrate areshields for protecting the electric device and the physical quantitysensor.

In the device, the electric device and the sensor are protected frommalfunctioning without any additional shield. Specifically, the deviceis protected from outside disturbance without adding an additionalshield. Thus, the number of the parts composing the device is reduced,and the manufacturing process of the device is also reduced, so that themanufacturing cost of the device is reduced.

Preferably, the first layer and the fourth layer are grounded.

Preferably, the electric device is disposed in the third layer of thefirst substrate. The physical quantity sensor is disposed in the sixthlayer of the second substrate. The second layer of the first substrateis made of an insulation layer so that the first and third layers areelectrically isolated. The fifth layer of the second substrate is madeof an insulation layer so that the fourth and sixth layers areelectrically isolated. More preferably, the physical quantity sensorincludes a movable portion disposed in the sixth layer. The movableportion is movable in accordance with a physical quantity applied to thedevice so that the physical quantity sensor outputs a signalcorresponding to a displacement of the movable portion. The firstsubstrate faces the second substrate so that the electric deviceelectrically connects to the physical quantity sensor. Furthermorepreferably, the second substrate includes a bump disposed on the sixthlayer of the second substrate. The third layer of the first substratefaces the sixth layer of the second substrate so that the firstsubstrate electrically is connected to the second substrate through thebump. The first layer of the first substrate and the fourth layer of thesecond substrate are disposed outside. Furthermore preferably, the firstand third layers of the first substrate are made of semiconductor. Thefourth and sixth layers of the second substrate are made ofsemiconductor. The electric device controls the physical quantitysensor, and the physical quantity sensor outputs the signal to theelectric device through the bump. Furthermore preferably, the physicalquantity sensor is an acceleration sensor, an angular rate sensor or apressure sensor. The first and second substrates are provided by asilicon-on-insulator substrate. The electric device is a signalprocessor.

Preferably, the device further includes a first loop layer disposed inthe third layer of the first substrate; and a second loop layer disposedin the sixth layer of the second substrate. The first and second looplayers are connected with a loop bump. The first and second loop layerswith the loop bump are shields for protecting the electric device andthe physical quantity sensor. More preferably, the first and second looplayers with the loop bump are grounded. Furthermore preferably, thefirst loop layer surrounds the electric device, and the second looplayer surrounds the physical quantity sensor. The loop bump has a loopshape. Furthermore preferably, the device further includes a firstshield layer disposed between the third layer and the second layer ofthe first substrate; and a second shield layer disposed between thesixth layer and the fifth layer. The first loop layer is electricallyconnected to the first shield layer through a first contact portion. Thesecond loop layer is electrically connected to the second shield layerthrough a second contact portion. The electric device and the physicalquantity sensor are covered with the first and second loop layers, thefirst and second contact portions, the first and second shield layersand the loop bump.

Further, a semiconductor device includes a first substrate includingfirst, second and third layers; and a second substrate. The firstsubstrate provides one of an electric device and a physical quantitysensor. The second substrate provides the other one of the electricdevice and the physical quantity sensor. The first layer of the firstsubstrate is a shield for protecting the electric device and thephysical quantity sensor.

In the device, the electric device and the sensor are protected frommalfunctioning without any additional shield. Specifically, the deviceis protected from outside disturbance without adding an additionalshield. Thus, the number of the parts composing the device is reduced,and the manufacturing process of the device is also reduced, so that themanufacturing cost of the device is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a cross sectional view showing a sensor module of asemiconductor device according to a first embodiment of the presentinvention;

FIG. 2 is a cross sectional view showing the detail of the sensormodule, according to the first embodiment;

FIG. 3 is a plan view showing a sensor chip of the device according tothe first embodiment;

FIG. 4 is a cross sectional view showing the sensor chip taken alongline IV-IV in FIG. 3;

FIG. 5 is a cross sectional view showing the semiconductor deviceaccording to the first embodiment;

FIG. 6 is a cross sectional view showing a sensor module of asemiconductor device according to a second embodiment of the presentinvention;

FIG. 7 is a plan view showing the first substrate of the device viewedfrom arrow VII-VII in FIG. 6;

FIGS. 8A-8F are cross sectional views explaining a manufacturing methodof the device according to the second embodiment;

FIG. 9 is a cross sectional view showing a sensor module of asemiconductor device according to a third embodiment of the presentinvention;

FIG. 10 is a cross sectional view showing the detail of the sensormodule, according to the third embodiment;

FIG. 11 is a cross sectional view showing a semiconductor deviceaccording to a fourth embodiment of the present invention;

FIG. 12 is a cross sectional view showing a semiconductor deviceaccording to a fifth embodiment of the present invention;

FIG. 13 is a cross sectional view showing a semiconductor deviceaccording to a sixth embodiment of the present invention;

FIG. 14 is a cross sectional view showing a sensor module of asemiconductor device according to modifications of the embodiments ofthe present invention;

FIG. 15 is a cross sectional view showing a semiconductor deviceaccording to the modifications of the embodiments;

FIG. 16 is a cross sectional view showing a semiconductor deviceaccording to the modifications of the embodiments; and

FIG. 17 is a cross sectional view showing a semiconductor deviceaccording to a prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

A semiconductor device 100 having a physical quantity sensor module 110according to a first embodiment of the present invention is shown inFIGS. 1-5. The sensor module 110 includes a capacitance typesemiconductor acceleration sensor. FIG. 1 shows a sensor module 110, andFIG. 2 shows the detail of the sensor module 110. The sensor module 110includes a sensor chip 52 and a signal processor 53. The sensor chip 52of the sensor module 110 is for example, shown in FIGS. 3 and 4. Thedevice 100 with the sensor module 110 is shown in FIG. 5, which is awhole construction including a package for accommodating the sensormodule 110 therein.

As shown in FIG. 1, the sensor module 110 includes the first and secondsubstrate 1, 2. The first substrate 1 for providing the signal processor53 includes the first silicon layer 1 a as the first semiconductorlayer, an oxide film 1 b as an insulation layer, and the second siliconlayer 1 c as the second semiconductor layer, all of which are stacked inthis order. Therefore, the first substrate 1 is a silicon-on-insulator(i.e., SOI) substrate having a rectangular shape. Similarly, the secondsubstrate 2 for providing the sensor chip 52 includes the first siliconlayer 2 a as the first semiconductor layer, an oxide film 2 b as aninsulation layer, and the second silicon layer 2 c as the secondsemiconductor layer, all of which are stacked in this order. Therefore,the second substrate 2 is a SOI substrate having a rectangular shape.

The second substrate 2 includes a movable portion 50 and multipleprotruded electrodes (i.e., bump electrodes) 11. The movable electrode50 is disposed on the second silicon layer 2 c separated from the firstsilicon layer 2 a by the oxide film 2 b. The bump electrodes 11 aredisposed around the movable portion 50. The bump electrode 11 connectsto a signal processing circuit (not shown) of the first substrate 1 sothat the second substrate 2 is electrically connected to the firstsubstrate 1 through the bump 11 electrodes. Thus, the second substrate 2provides a flip chip bonding type semiconductor substrate (i.e., a flipchip type substrate). Here, the signal processing circuit is disposed inthe second silicon layer 1 c separated from the first silicon layer 1 aby the oxide film 1 b. Thus, the first substrate 1 is electricallyconnected to the second substrate 2 without a wire. Therefore, aparasitic capacitance generated in the sensor module 110 is reduced.

Thus, the first substrate 1 and the second substrate 2 are connectedtogether with the flip chip type connection method. Therefore, themovable portion 50 faces the principal plane of the first substrate 1. Aclosed spacing 71 is disposed between the movable portion 50 and theprincipal plane of the first substrate 1 in order to prevent the movableportion 50 from contacting the principal plane of the first substrate 1.The first substrate 1 also works as a stopper for limiting a movableelectrode 60 of the movable portion 50 from moving toward an oppositedirection of the principal plane of the second substrate 2 withoutlimitation.

FIGS. 3 and 4 show the sensor chip 52 of the sensor module 110 havingthe movable portion 50 being used for an acceleration sensor. The sensorchip 52 includes the movable portion 50 having the movable electrode 60and a fixed electrode 61. The movable electrode 60 is movably supportedon a beam 62. The fixed electrode 61 faces the movable electrode 60 sothat a capacitor having a capacitance is formed therebetween. Therefore,a clearance is formed between the fixed electrode 61 and the movableelectrode 60. The fixed electrode 61 also works as an electrode of anelectric device for detecting a capacitance change of the capacitor inaccordance with the displacement of the movable electrode 60.

As shown in FIG. 5, the sensor module 110 is accommodated in a package3, which is composed of a base 3 a and a cover 3 b. Specifically, thesensor module 110 is disposed on the bottom of the base 3 a having aconcavity through a conductive adhesion 4 a. The upper portion of thesensor module 110 is covered with the cover 3 b. The cover 3 b is bondedto the base 3 a with an adhesion 4 b. If necessary, the cover 3 b andthe base 3 a are bonded in vacuum, or dry air or dry nitrogen gas isintroduced into the package 3, so that the package 3 is sealedair-tightly. The package 3 is made of, for example, ceramics, and theadhesion 4 b is, for example, adhesion bond or brazing metal.

The first electrode pad 5 a is disposed on a predetermined position ofone side of the first substrate 1. A metal layer 5 b is disposed on oneside of the second substrate 2, which is opposite to the movable portion50. Specifically, the metal layer 5 b is formed on all surface of theone side of the second substrate 2. The second electrode pad 5 c isdisposed on a predetermined position of the package 3. The secondelectrode pad 5 c is electrically connected to the third electrode pad 5d through a via-hole formed in the base 3 a. Therefore, the first andsecond electrode pads 5 a, 5 c are electrically connected with a wire54, and the metal layer 5 b and the second electrode pad 5 c areelectrically connected with the wire 54 so that the first and secondsubstrate 1, 2 and the package 3 are electrically connected together.

Thus, a signal outputted from the sensor module 110 to the package 3 isoutputted from the third electrode pad 5 d disposed on the periphery ofthe package 3 to an outside circuit outside the package 3 through aninner wiring (not shown) of the package 3. The first electrode pad 5 ais made of, for example, aluminum. The second and third electrode pads 5c, 5 d are made of, for example, copper, nickel, gold or their laminatedmaterial. The wire 54 is made of, for example, aluminum or gold.

A lower electrode 6 is disposed on the base 3 a of the package 3 anddisposed under the sensor 100. The lower electrode 6 and the thirdelectrode pad 5 d are electrically connected through another innerwiring (not shown) of the package 3 so that the signal is outputted tothe outside circuit.

In this embodiment, the first and second substrates 1, 2 are provided bythe SOI substrate. The signal processor 53 is formed in the secondsilicon layer 1 c of the first substrate 1, which is electricallyinsulated from the first silicon layer 1 a by the oxide film 1 b. Themovable portion 50 is formed in the second silicon layer 2 c of thesecond substrate 2, which is electrically insulated from the firstsilicon layer 2 a by the oxide film 2 b. The second silicon layer 1 c ofthe first substrate 1, in which the signal processor 53 is disposed, iselectrically connected through the bump electrode 11 to the secondsilicon layer 2 c of the second substrate 2, in which the movableportion 50 is disposed. Thus, the first silicon layer 1 a of the firstsubstrate 1 and the first silicon layer 2 a of the second substrate 2work as a shield layer for protecting the movable portion 50 and thesignal processor 53 from outside disturbance such as noise.Specifically, they prevent the movable portion 50 and the signalprocessor 53 from malfunctioning.

The first silicon layer 1 a of the first substrate 1 is isolated fromthe signal processor 53 formed in the second silicon layer 1 c by theoxide film 1 b. The first silicon layer 2 a of the second substrate 2 isisolated from the movable portion 50 by the oxide film 2 b. Therefore,the electrical potential of each of the first silicon layers 1 a, 2 adoes not affect the movable portion 50 and the signal processor 53.

Accordingly, the electric potentials of the first silicon layers 1 a, 2a can be set to be predetermined values, which are determinedindependently from electric potentials of the signal processor 53 andthe movable portion 50. Therefore, the electric potentials of the firstsilicon layers 1 a, 2 a can be ground potential, so that the firstsilicon layers 1 a, 2 a work as the shield layer for preventing themovable portion 50 and the signal processor 53 from malfunctioning.

Therefore, the semiconductor device 100 can have the movable portion 50and the signal processor 53 protected from malfunctioning without anyadditional shield. Specifically, the device 100 is protected fromoutside disturbance without adding an additional shield. Thus, thenumber of the parts composing the device 100 is reduced, and themanufacturing process of the device 100 is also reduced, so that themanufacturing cost of the device 100 is reduced.

Second Embodiment

A semiconductor device 200 having a sensor module 210 according to asecond embodiment of the present invention is shown in FIGS. 6-7. Thesensor module 210 includes the first and second loop layers 1 d, 2 d.The first loop layer 1 d is formed in the second silicon layer 1 c ofthe first substrate 1, which includes the signal processor 53. Thesecond loop layer 2 d is formed in the second silicon layer 2 c of thesecond substrate 2, which includes the movable portion 50. The firstloop layer 1 d is electrically connected to the second loop layer 2 dthrough a loop bump 11 a.

The first loop layer 1 d of the first substrate 1 is electricallyinsulated from the other portion of the second silicon layer 1 c of thefirst substrate 1 by a loop insulation portion 1 e, the other portionbeing except for the first loop layer 1 d. The first poly crystallinesilicon layer 1 f is disposed between the first silicon layer 1 a andthe oxide film 1 b. The first poly crystalline silicon layer 1 f iselectrically connected to the first loop layer 1 d through the firstcontact portion 1 g. The loop insulation portion 1 e is made of, forexample, insulation material such as silicon oxide film.

The second poly crystalline silicon layer 2 f is disposed between thefirst silicon layer 2 a and the oxide film 2 b. The second polycrystalline silicon layer 2 f is electrically connected to the secondloop layer 2 d through the second contact portion 2 g.

As shown in FIG. 7, the first loop layer 1 d is disposed on a region,which is electrically insulated from the other portion of the secondsilicon layer 1 c of the first substrate 1 by the loop insulationportion 1 e. The loop insulation portion 1 e is formed in the secondsilicon layer 1 c of the first substrate 1, which includes the signalprocessor 53. The loop bump 11 a is disposed on the first loop layer 1 dso that the second loop layer 2 d formed in the second silicon layer 2 cof the second substrate 2, which includes the movable portion 50, iselectrically connected to the first loop layer 1 d through the loop bump11 a.

Further, the fourth electrode pad 5 e is formed in the second siliconlayer 1 c of the first substrate 1, which includes the signal processor53. The bump electrode 11 is disposed on the fourth electrode pad 5 e.The sensor chip 52 of the second substrate 2 is electrically connectedto the signal processor 53 of the first substrate 1 through the bumpelectrode 11. The first electrode pad 5 a is disposed on a periphery ofthe second silicon layer 1 c of the first substrate 1, which includesthe signal processor 53. The fourth electrode pad 5 e is electricallyconnected to the first electrode pad 5 a through a wire layer 7 so thatthe signal is outputted from the sensor chip 52 disposed on the secondsubstrate 2 and the signal processor 53 disposed on the first substrate1 to the outside circuit. The wire layer 7 is made of, for example,aluminum and the like.

An electric circuit (not shown) is disposed on a periphery of the secondsilicon layer 1 c of the first substrate 1. The fifth electrode pad 5 ffor connecting to the electric circuit is disposed on the second siliconlayer 1 c of the first substrate 1. The fifth electrode pad 5 f performsto connect to the electric circuit.

The sixth electrode pad 5 g for connecting to inner circuits is disposedinside of the loop insulation portion 1 e of the second silicon layer 1c of the first substrate 1. The sixth electrode pad 5 g performs toconnect between the inner circuits disposed inside of the loopinsulation portion 1 e. Further, the seventh electrode pad 5 h forcontrolling the electric potential of the first loop layer 1 d isdisposed on a periphery of the second silicon layer 1 c of the firstsubstrate 1. The eighth electrode pad 5 i is disposed on the first looplayer 1 d. The seventh electrode pad 5 h and the eighth electrode pad 5i are electrically connected together with the wire layer 7 so that theelectric potential of the first loop layer 1 d is controlled (i.e.,adjusted).

An insulation layer (not shown) is formed between the wire layer 7 andthe loop bump 11 a so that the wire layer 7 and the loop bump 11 a areelectrically isolated. Specifically, the insulation layer is disposed atleast on a region, at which the wire layer 7 and the loop bump 11 aoverlap.

The sensor module 210 is manufactured by the following method, as shownin FIGS. 8A-8F. Here, the manufacturing method for manufacturing thesecond substrate 2 is described as follows. However, the first substrate1 can be also manufactured by almost the similar method. As shown inFIG. 5A, the first silicon wafer 30 is prepared. The first silicon wafer30 includes an impurity (i.e., dopant) having N type conductivity suchas phosphorus (i.e., P) or arsen (i.e., As). The first silicon wafer 30has specific resistance between 0.001Ω·cm and 10Ω·cm. Preferably, thespecific resistance is between 0.001Ω·cm and 0.1Ω·cm. A thermaloxidation film 31 is formed on one side of the first silicon wafer 30 byusing thermal oxidation method. A contact hole 31 a is formed in thethermal oxidation film 31 at a predetermined position by usingphotolithography and the like.

As shown in FIG. 5B, a poly crystalline silicon film 32 is formed on thethermal oxidation film 31 having the contact hole 31 a by using the CVD(i.e., chemical vapor deposition) method and the like. The polycrystalline silicon film 32 includes a large amount of impurities havingN type conductivity such as P or As, i.e., the poly crystalline siliconfilm 32 includes the impurities at high concentration (e.g., between1×10¹⁶cm⁻³ and 1×10²¹cm⁻³). Then, the surface of the poly crystallinesilicon film 32 is polished so as to obtain mirror surface.

As shown in FIG. 5C, the second silicon wafer 33 is prepared. The secondsilicon wafer 33 includes an impurity having N type conductivity such asP or As. The second silicon wafer 33 has specific resistance between0.001Ω·cm and 10Ω·cm. Preferably, the specific resistance is between0.001Ω·cm and 0.1Ω·cm. Thus, the specific resistance of the secondsilicon wafer 33 is almost the same as that of the first silicon wafer30.

As shown in FIG. 5D, the poly crystalline silicon film 32 of the firstsilicon wafer 30 is bonded to one side of the second silicon wafer 33.This bonding is performed in inert gas such as nitrogen gas.

As shown in FIG. 5E, the other side of the first silicon wafer 30, whichis opposite to the poly crystalline silicon film 32, is polished so thatthe first silicon wafer 30 is thinned. And the first silicon wafer 30with the second silicon wafer 33 is turned upside down.

As shown in FIG. 5F, the movable portion 50 is formed in the firstsilicon wafer 30 by using the dry-etching method and the like. Here, themovable portion 50 provides an acceleration sensor. The movable portion50 is electrically connected to a bump 35 a. At that time, a loop layer34 is formed at a periphery of the first silicon wafer 30. A bump 35 ais disposed on the first silicon wafer 30, and another bump 35 b isdisposed on the loop layer 34 so that the sensor chip 52 of the secondsubstrate 2 and the signal processor 53 of the first substrate 1 areelectrically connected together with the bumps 35 a, 35 b. The bumps 35a, 35 b are made of a multi-layered material. The multi-layered materialis provided by a combination of nickel (i.e., Ni) copper (i.e., Cu) andgold (i.e., Au) deposited on aluminum layer.

In the second embodiment, the first loop layer 1 d is formed in thesecond silicon layer 1 c of the first substrate 1, which includes thesignal processor 53. The second loop layer 2 d is formed in the secondsilicon layer 2 c of the second substrate 2, which includes the movableportion 50. The first and second loop layers 1 d, 2 d are electricallyconnected together with the loop bump 11 a.

The first loop layer 1 d of the first substrate 1 is electricallyisolated from the other portion of the second silicon layer 1 c of thefirst substrate 1 by the loop insulation portion 1 e. The other portionis disposed except for the first loop layer 1 d. The poly crystallinesilicon layer 1 f disposed between the first silicon layer 1 a and theoxide film 1 b is electrically connected to the first loop layer 1 dthrough the first contact portion 1 g.

The second loop layer 2 d is electrically connected to the second polycrystalline silicon layer 2 f through the second contact portion 2 g.The second poly crystalline silicon layer 2 f is disposed between thefirst silicon layer 2 a and the oxide film 2 b of the second substrate2.

The first silicon layer 1 a of the first substrate 1, the first looplayer 1 d of the first substrate 1, the first silicon layer 2 a of thesecond substrate 2, and the second loop layer 2 d of the secondsubstrate 2 work as the shield for protecting the movable portion 50 andthe signal processor 53 from malfunctioning by the outside noise and thelike.

Therefore, the device 200 can have the movable portion 50 and the signalprocessor 53 protected from malfunctioning without any additionalshield. Thus, the number of the parts composing the device 200 isreduced, and the manufacturing process of the device 200 is alsoreduced, so that the manufacturing cost of the device 200 is reduced.

Third Embodiment

A semiconductor device 300 having a sensor module 310 according to athird embodiment of the present invention is shown in FIGS. 9 and 10.The sensor module 310 includes the first and second loop layers 1 d, 2d. The first loop layer 1 d is formed in the second silicon layer 1 c ofthe first substrate 1, and the second loop layer 2 d is formed in thesecond silicon layer 2 c of the second substrate 2. The first loop layer1 d of the first substrate 1 is electrically isolated from the firstsilicon layer 1 a of the first substrate 1 by the oxide film 1 b. Thesecond loop layer 2 d of the second substrate 2 is electrically isolatedfrom the first silicon layer 2 a of the second substrate 2 by the oxidefilm 2 b. In this embodiment, the sensor module 310 does not include thefirst and second poly crystalline silicon layers 1 f, 2 f and the firstand second contact portions 1 g, 2 g.

As shown in FIG. 10, the movable portion 50 is formed in the secondsilicon layer 2 c of the second substrate 2. The movable portion 50includes multiple movable electrodes 60 and fixed electrodes 61. Themovable electrodes face the fixed electrodes, respectively. Theseparation layer 1 h is formed on the surface of the second siliconlayers 1 c, 2 c of the first and second substrates 1, 2. The separationlayer 1 h is made of, for example, silicon oxide film. Multiple openingsare formed in the separation layer 1 h at predetermined positions sothat the bumps 11, 11 a are formed in the openings. Multiple electricdevices (not shown) are formed inside the second silicon layer 1 c ofthe first substrate 1. These electric devices are isolated together withthe loop insulation portion 1 e as an insulator. The loop insulationportion 1 e is made of silicon oxide film and the like.

The first silicon layer 1 a of the first substrate 1, the first looplayer 1 d of the first substrate 1, the first silicon layer of thesecond substrate 2, and the second loop layer 2 d of the secondsubstrate 2 work as the shield for protecting the movable portion 50 andthe signal processor 53 from malfunctioning by the outside noise and thelike.

Therefore, the device 300 can have the movable portion 50 and the signalprocessor 53 protected from malfunctioning without any additionalshield. Thus, the number of the parts composing the device 300 isreduced, and the manufacturing process of the device 300 is alsoreduced, so that the manufacturing cost of the device 300 is reduced.

Fourth Embodiment

A semiconductor device 400 having a sensor module 410 according to afourth embodiment of the present invention is shown in FIG. 11. Althoughthe sensor module 110 shown in FIG. 2 is accommodated in the package 3,the sensor module 410 is sealed with a resin mold 57 so that the device400 is provided.

Specifically, the sensor module 410 is mounted on a die pad 55 of thelead frame. The first substrate 1 is electrically connected to an innerlead 56 through a wire 54. The sensor module 410 together with the diepad 55 and the inner lead 56 are sealed with the resin mold 57 so that aresin mold package is formed.

The device 400 can have the movable portion 50 and the signal processor53 protected from malfunctioning without any additional shield so thatthe manufacturing cost of the device 400 is reduced.

Fifth Embodiment

A semiconductor device 500 having a sensor module 510 according to afifth embodiment of the present invention is shown in FIG. 12. Althoughthe sensor module 110 shown in FIG. 2 is electrically connected to thepackage 3 through the wire 54, the sensor module 510 is electricallyconnected to the package 3 through a bump 11 b.

Specifically, the first substrate 1 of the sensor module 510 isconnected to the package 3 through the bump 11 b. The second substrate 2is disposed downside of the sensor module 510. The second substrate 2 issupported to the first substrate 1, which is connected to the package 3.The second substrate 2 is accommodated in a concavity 3 c disposed onthe bottom of the package 3. The second substrate 2 is separated fromthe bottom of the package 3.

The device 500 can have the movable portion 50 and the signal processor53 protected from malfunctioning without any additional shield so thatthe manufacturing cost of the device 500 is reduced.

Sixth Embodiment

A semiconductor device 600 having a sensor module 610 according to asixth embodiment of the present invention is shown in FIG. 13. Thesensor module 610 is electrically connected to the package 3 through thebump 11 b.

Specifically, the first substrate 1 of the sensor module 610 isconnected to the package 3 through the bump 11 b. The second substrate 2is disposed downside of the sensor module 610. The second substrate 2 issupported to the first substrate 1, which is connected to the package 3.The second substrate 2 is accommodated in the concavity 3 c disposed onthe bottom of the package 3. The second substrate 2 is separated fromthe bottom of the package 3.

The sensor module 610 includes the first and second loop layers 1 d, 2d. The first loop layer 1 d is formed in the second silicon layer 1 c ofthe first substrate 1, and the second loop layer 2 d is formed in thesecond silicon layer 2 c of the second substrate 2.

The first silicon layer 1 a of the first substrate 1, the first looplayer 1 d of the first substrate 1, the first silicon layer 2 a of thesecond substrate 2, and the second loop layer 2 d of the secondsubstrate 2 work as the shield for protecting the movable portion 50 andthe signal processor 53 from malfunctioning by the outside noise and thelike.

Therefore, the device 600 can have the movable portion 50 and the signalprocessor 53 protected from malfunctioning without any additional shieldso that the manufacturing cost of the device 600 is reduced.

(Modifications)

Although the sensor modules 110-610 provide the capacitance typesemiconductor acceleration sensor, the sensor modules 110-610 canprovide a semiconductor sensor such as an angular rate sensor or apressure sensor.

Although the first substrate 1 of each sensor module 110-310, 510 isconnected to the package 3, the second substrate 2 of each sensor module110-310, 510 can be connected to the package 3.

Although the conductive adhesion 4 a for bonding between the firstsubstrate 1 and the package 3 is applied to the whole surface of bondingsurfaces of the first substrate 1 and the package 3, the conductiveadhesion 4 a can be applied to a part of the bonding surfaces of thefirst substrate 1 and the package 3. For example, the conductiveadhesion 4 a is applied to four corners, a center, or a loop shaped partof the bonding surface. That is because the stress generated in thesensor 100-300 becomes smaller.

Although the first and second silicon wafers 30, 33 in the manufacturingprocess for manufacturing the sensor 200 shown in FIGS. 8A-8F includethe impurity having N type conductivity such as P or As, other siliconwafers can be used as the wafers 30, 33. For example, the wafer includesan impurity having P type conductivity such as boron (i.e., B).

Although the first and second substrates 1, 2 are provided by the SOIsubstrate, at least one of the first and second substrates 1, 2 can beprovided by the SOI substrate in some cases that depends on a mountingstate of the first and second substrates 1, 2 mounted on the package 3.

FIG. 14 is a cross sectional view showing a sensor module 710 having thefirst substrate 1 formed of a bulky substrate provided by singlecrystalline silicon wafer. FIG. 15 shows a semiconductor device 700having the sensor module 710 shown in FIG. 14. The sensor module 710 isaccommodated in the package 3 made of ceramics. FIG. 16 shows asemiconductor device 701 having the sensor module 710 shown in FIG. 14.The sensor module 700 is sealed with the resin mold 57. In these cases,the first substrate 1 is provided by the single crystalline siliconwafer, and only the second substrate 2 is provided by the SOI substrate.

Although the sensor modules 110-710 include two substrates 1, 2, thesensor modules 110-710 can include multiple substrates including thesecond substrate 2. In this case, the multiple substrates except for thesecond substrate 2 face the second substrate 2, and the multiplesubstrates perform similar function of the first substrate 1 ordifferent function of the first substrate 1.

Such changes and modifications are to be understood as being within thescope of the present invention as defined by the appended claims.

What is claimed is:
 1. A semiconductor device comprising: a firstsubstrate including first, second and third layers, which are stacked inthis order; a second substrate; and a loop bump, wherein the first layeris made of silicon, the second layer is made of an insulation material,and the third layer is made of silicon, wherein the first substrateprovides a physical quantity sensor, wherein the second substrateprovides an electric device, wherein the physical quantity sensorincludes a movable electrode, a fixed electrode and a loop layer, whichare disposed in the third layer, wherein the movable electrode and thefixed electrode are insulated by the second layer, wherein the physicalquantity sensor detects a physical quantity based on a capacitancebetween the movable electrode and the fixed electrode, wherein the looplayer in the third layer is coupled with the second substrate via theloop bump, wherein the loop bump is disposed between the first andsecond substrates, and surrounds the movable portion, wherein the secondsubstrate includes an inner pad, an outer pad and a wire layer, whereinthe inner pad is disposed inside of the loop bump, and the outer pad isdisposed outside of the loop bump, wherein the inner pad is electricallycoupled with the outer pad through the wire layer, and wherein the wirelayer is electrically insulated from the loop bump.
 2. The deviceaccording to claim 1, wherein the wire layer is insulated from the loopbump with an insulation film.
 3. The device according to claim 1,wherein the wire layer is made of aluminum.
 4. The device according toclaim 1, wherein the second substrate includes fourth to sixth layers,which are stacked in this order, wherein the fourth layer is made ofsilicon, the fifth layer is made of an insulation material, and thesixth layer is made of silicon, wherein the electric device is disposedin the sixth layer of the second substrate, wherein the third layer ofthe first substrate faces the sixth layer of the second substrate, andwherein the fourth and sixth layers are electrically isolated with thefifth layer.
 5. The device according to claim 4, wherein the movableportion is movable in accordance with the physical quantity applied tothe device so that the physical quantity sensor outputs the signalcorresponding to a displacement of the movable portion, and wherein theelectric device electrically connects to the physical quantity sensor.6. The device according to claim 5, wherein the second substrateincludes a bump disposed on the sixth layer, wherein the secondsubstrate is electrically connected to the first substrate through thebump, and wherein the fourth layer of the second substrate and the firstlayer of the first substrate are disposed outside.
 7. The deviceaccording to claim 6, wherein the electric device controls the physicalquantity sensor, and the physical quantity sensor outputs the signal tothe electric device through the bump.
 8. The device according to claim7, wherein the physical quantity sensor is an acceleration sensor, anangular rate sensor or a pressure sensor, and wherein the electricdevice is a signal processor.
 9. The device according to claim 1,wherein the movable portion is sandwiched by the first and secondsubstrates, wherein the sixth layer of the second substrate includes asecond loop layer, which surrounds the movable portion, wherein the looplayer in the first substrate surrounds the movable portion, and whereinthe loop layer in the first substrate is electrically connected to thesixth layer of the second substrate with the loop bump so that themovable portion is shielded.
 10. The device according to claim 9,wherein the first substrate further includes a first poly crystallinesilicon layer, which is sandwiched between the first and second layers,wherein the second substrate further includes a second poly crystallinesilicon layer, which is sandwiched between the fourth and fifth layers,wherein the loop layer of the first substrate is isolated from the thirdlayer with a first loop insulation portion, wherein the second looplayer of the second substrate is isolated from the sixth layer with asecond loop insulation portion, wherein the second loop layer of thesecond substrate is electrically coupled with the second polycrystalline silicon layer, and the loop layer of the first substrate iselectrically coupled with the first poly crystalline silicon layer, andwherein the second loop layer of the second substrate is electricallycoupled with the loop layer of the first substrate with the loop bump.